Bug 1660901 - Add some test cases for fstatat inside the content sandbox. r=gcp

Differential Revision: https://phabricator.services.mozilla.com/D88500

security/sandbox/common/test/SandboxTestingChild.cpp

@@ -3,9 +3,19 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
 #include "SandboxTestingChild.h"
 #include "SandboxTestingThread.h"
 
+#include "nsXULAppAPI.h"
+
+#ifdef XP_UNIX
+#  include <fcntl.h>
+#  include <sys/stat.h>
+#  include <sys/types.h>
+#  include <unistd.h>
+#endif
+
 namespace mozilla {
 
 SandboxTestingChild* SandboxTestingChild::sInstance = nullptr;
@@ -50,11 +60,28 @@ void SandboxTestingChild::Bind(Endpoint<PSandboxTestingChild>&& aEndpoint) {
   DebugOnly<bool> ok = aEndpoint.Bind(this);
   MOZ_ASSERT(ok);
 
-  // Placeholder usage of the APIs needed to report test results.
+  if (XRE_IsContentProcess()) {
-  // This will be fleshed out with tests that are OS and process type dependent.
+#ifdef XP_UNIX
-  SendReportTestResults(nsCString("testId1"), true /* shouldSucceed */,
+    struct stat st;
-                        true /* didSucceed*/,
+    static const char kAllowedPath[] = "/usr/lib";
-                        nsCString("These are some test results!"));
+
+    ErrnoTest("fstatat_as_stat"_ns, true,
+              [&] { return fstatat(AT_FDCWD, kAllowedPath, &st, 0); });
+    ErrnoTest("fstatat_as_lstat"_ns, true, [&] {
+      return fstatat(AT_FDCWD, kAllowedPath, &st, AT_SYMLINK_NOFOLLOW);
+    });
+#  ifdef XP_LINUX
+    ErrnoTest("fstatat_as_fstat"_ns, true,
+              [&] { return fstatat(0, "", &st, AT_EMPTY_PATH); });
+#  endif  // XP_LINUX
+#else     // XP_UNIX
+    SendReportTestResults("dummy_test"_ns,
+                          /* shouldSucceed */ true,
+                          /* didSucceed */ true,
+                          "The test framework fails if there are no cases."_ns);
+#endif    // XP_UNIX
+  }
+
   // Tell SandboxTest that this process is done with all tests.
   SendTestCompleted();
 }
@@ -77,4 +104,26 @@ bool SandboxTestingChild::RecvShutDown() {
   return true;
 }
 
+#ifdef XP_UNIX
+template <typename F>
+void SandboxTestingChild::ErrnoTest(const nsCString& aName, bool aExpectSuccess,
+                                    F&& aFunction) {
+  int status = aFunction() >= 0 ? 0 : errno;
+  PosixTest(aName, aExpectSuccess, status);
+}
+
+void SandboxTestingChild::PosixTest(const nsCString& aName, bool aExpectSuccess,
+                                    int aStatus) {
+  bool succeeded = aStatus == 0;
+  nsAutoCString message;
+  if (succeeded) {
+    message = "Succeeded"_ns;
+  } else {
+    message.AppendPrintf("Error: %s", strerror(aStatus));
+  }
+
+  SendReportTestResults(aName, aExpectSuccess, succeeded, message);
+}
+#endif  // XP_UNIX
+
 }  // namespace mozilla

security/sandbox/common/test/SandboxTestingChild.h

@@ -11,6 +11,10 @@
 #include "mozilla/Monitor.h"
 #include "mozilla/UniquePtr.h"
 
+#ifdef XP_UNIX
+#  include "nsString.h"
+#endif
+
 #if !defined(MOZ_SANDBOX) || !defined(MOZ_DEBUG) || !defined(ENABLE_TESTS)
 #  error "This file should not be used outside of debug with tests"
 #endif
@@ -41,6 +45,17 @@ class SandboxTestingChild : public PSandboxTestingChild {
                                Endpoint<PSandboxTestingChild>&& aEndpoint);
   void Bind(Endpoint<PSandboxTestingChild>&& aEndpoint);
 
+#ifdef XP_UNIX
+  // For test cases that return an error number or 0, like newer POSIX APIs.
+  void PosixTest(const nsCString& aName, bool aExpectSuccess, int aStatus);
+
+  // For test cases that return a negative number and set `errno` to
+  // indicate error, like classical Unix APIs; takes a callable, which
+  // is used only in this function call (so `[&]` captures are safe).
+  template <typename F>
+  void ErrnoTest(const nsCString& aName, bool aExpectSuccess, F&& aFunction);
+#endif
+
   UniquePtr<SandboxTestingThread> mThread;
 
   static SandboxTestingChild* sInstance;